The state of the art in tortilla counter-stackers is the counter-stacker manufactured by Arr-Tech Mfg., Inc. This device suffers from a severe drawback, in that the tortillas stacked by this device are not coaxially aligned, resulting in stacks having ragged edges like a deck of cards immediately after shuffling. Also like a deck of cards, the stacks of tortillas have to be manually tapped on the sides to obtain a smooth-sided cylindrical stack. In an industry where the production of tortillas is almost totally automated, this manual stack-aligning step adds substantial labor cost. It is estimated that for tortillas only 20% of the cost is in the product and 80% is in the labor-intensive packaging process. Automated stack-aligning would eliminate a half to two-thirds of the labor involved in packaging.
Numerous innovations for Tortilla Counter-Stackers have been provided in the prior art that are described as follows. Even though these innovations may be suitable for the specific individual purposes to which they address, they differ from the present invention as hereinafter contrasted.
In U.S. Pat. No. 4,760,777, titled Tortilla Stacker, invented by Richard S. Welsh, an apparatus for stacking tortillas includes a loading unit in the form of a trough-like loading conveyor for transporting a series of dough members while forming a small depression in each of the dough members. A container in the form of an upright hollow cylinder having a retractable loading surface is positioned at the discharge end of the loading conveyor. The tortillas are stacked one-on-top-of-the-other on the retractable loading surface by the loading conveyor. A conveyor located beneath the container receives the stack of tortillas upon retraction of the loading surface. A counter on an inclined chute leading to the conveyor accurately counts the number of tortillas entering the container.
In U.S. Pat. No. 4,006,831, titled Automatic Tortilla Counter and Stacker, invented by James A. Jimenez, a method of stacking articles and an automatically controlled apparatus for successively receiving articles formed of rigid or semirigid sheet material such as cooked or partially cooked tortillas or similar food products, automatically formed orderly stacks of a predetermined number of articles, and then automatically carrying away for packaging each stack when completed.
In U.S. Pat. No. 4,530,632, titled Stacking Apparatus for Flexible, Generally Planar Food Products, invented by Richard Sela, an apparatus for counting and stacking food products such as tortillas. The tortillas are initially placed on an entry chute containing a large number of air outlets for creating a cushion of air to allow the tortilla to slide down the entry chute onto an incline conveyor belt. The conveyor belt is of an open mesh design and it is supported on a belt support having a large number of air inlets which create a vacuum that maintains the tortilla in contact with the belt. The tortillas are carried by the belt down one end of the belt support and along the underside of the belt support with contact between the tortilla and belt being maintained by vacuum creating air inlets formed in the belt support. The air inlets terminate at a location on the underside of the belt support thereby allowing the tortillas to drop from the conveyor belt. The tortillas drop onto a stationary rack formed by rods which are interleaved with conveyor belts moving together as a unit. The conveyor belts are normally positioned beneath the upper surface of the rack. However, when a predetermined number of tortillas have been stacked, the belt is lifted thereby carrying the tortillas from the rack. The mechanism for lifting the belts is actuated by a counter which counts a predetermined number of tortillas passing past a counting station and delays actuating the belt lifting mechanism until the final tortilla has dropped onto the rack. The belts discharging the stacks of tortillas move in the direction opposite the direction that the tortillas are delivered to the rack in order to minimize the time required to remove the tortillas from the rack before an additional tortilla may be placed thereon.
In U.S. Pat. No. 5,720,593, titled Apparatus and Method of Counting, Inspecting and Stacking Planar Food Products, invented by Todd B. Pleake, an apparatus for counting, inspecting, and stacking flexible, generally planar food products such as tortillas, or the like. The apparatus has an inclined infeed conveyor with adjustable alignment guides thereon to adjust the lateral position of each tortilla as it moves to a transit conveyor. Sensors mounted on the transit conveyor count the tortillas and inspect the size and shape of the tortillas to detect any defective tortillas moving along the transit conveyor. At the end of the transit conveyor, an arcuate-shaped trajectory guide bends the tortilla into an arcuate shape as the tortilla leaves the trajectory guide and flies through a known flight trajectory to a stacking mechanism. The arcuate shape allows the leading edge of the tortilla to resist bending or folding. A rejection mechanism positioned between the end of the transit conveyor and the trajectory guide redirects any rejected tortillas detected by the sensors downward away from the trajectory guide. A stacking mechanism receives the tortillas at the end of the flight trajectory. A shaker shakes the stacking mechanism and jostles the stack of tortillas to form a tight, aligned stack. A movable stack plate supports the stack of tortillas in the stacking mechanism and moves downward incrementally as tortillas are stacked into the stacking mechanism so the flight trajectory of each tortilla is approximately the same. The stacking plate has a lowered position that deposits a stack of tortillas on a baseplate, and a stack removal device moves the stack of tortillas away from the stacking assembly to a discharge conveyor.
In U.S. Pat. No. 5,253,762, titled Stacking, Counting and Sorting Device for Flexible, Planar Food Products, invented by Daryl G. Duncan, a device for counting, inspecting, sorting, and stacking planar food products such as tortillas. The tortillas are sandwiched between a pair of conveyor belts moving at the same speed to a discharge location between a pair of rollers around which the respective conveyor belts extend. The speed of the tortillas causes them to be flung from between the rollers onto a discharge tray. A counter determines when a predetermined number of tortillas have been discharged onto the discharge tray. The counter then triggers an actuator to remove the tray from beneath the stack of tortillas, thereby allowing them to fall onto a discharge conveyor belt. The discharge conveyor belt is then moved an incremental distance. The tortillas passing through the device are scanned in order to detect defective tortillas. When a defective tortilla is found, one of the rollers at the discharge location is shifted, thereby altering the path of the tortillas flung from the conveyor belts at the discharge location onto a reject discharge conveyor belt.
In U.S. Pat. No. 5,601,397, titled Apparatus for Counting and Stacking Tortillas, invented by Manuel Lopez and Rafael Lopez, an apparatus having a series of conveyor belts for flattening and stacking a plurality of flexible, generally planar articles, such as tortillas. The apparatus includes a first conveyor belt extending along first end, upper, second end and lower surfaces of a belt support. The conveyor belt is adapted to move the planar articles placed on the upper surface of the belt support from the first end to the second end. A second conveyor belt is biased against the first belt at the second end of the belt support for applying compressive and lateral forces to the planar articles as they are moved along the second end of the belt support. A third conveyor belt is located beneath the first and second conveyor belts for receiving the planar articles from the first belt, forming stacks of them, and then discharging the stacked planar articles. Motor assemblies drive the first, second, and third conveyor belts.
In U.S. Pat. No. 4,054,015, titled Chip Packing Apparatus and Method, invented by Lorne A. Rowell, invented by Lorne A. Rowell, an apparatus for stacking food chips in a cylindrical container. Random chips are oriented into tandem alignment on an inclined conveyor traveling in an upward direction and are deposited into an upright cylindrical stacking tube above a station for the empty cylindrical containers. A valve comprising operatively associated upper and lower blades in the stacking tube load vertical stacks of chips into the cylindrical containers.
In U.S. Pat. No. 3,915,316, titled Counting and stacking Apparatus, invented by Johnny B. Pomara, Jr., apparatus for counting and stacking substantially flat articles, such, particularly, as food articles of the nature of Mexican tortillas, which includes a first belt type feed conveyor, a second belt type stacking conveyor intermeshing with a vertically movable stacking rack or fork, and a take-away conveyor. The articles are sequentially fed from a conventional conveyor from apparatus such as an oven to the feed conveyor beneath a counting switch. Each article is discharged from the feed conveyor in a stacked relationship to the stacking conveyor against the stacking rack. When the desired number of articles are stacked on the stacking conveyor against the rack, the rack rapidly retracts downwardly releasing the stack for discharge to the take-away conveyor. Between the time of discharge of each stack and the arrival of the first article for forming the next stack, the stacking rack returns upwardly to intermeshed relationship with the stacking conveyor for forming and holding the next stack.
The above patented inventions differ from the present invention because they fail to describe or claim at least one combination of the following features depicted in the present invention: canister with canister sleeve, vibrator, stacker, lift, upper conveyor, lower conveyor, photoelectric eye, and counter.